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Full text of "Large pile concrete trestles."

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APR 6 1936 





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They Look the Part. The large-pile ti lie has clean-cut lines 
eloquent of great reserve strength, stability and permanence. 




Fewer Bents Needed. New 18 ft. spans 

replacing old pans of 14 ft. or less. 

Greater Load Capacity. 

Showing field test l - ! of 105 
I • 110 tons on single 2 \ fa 
pile, consisting of weight of 
crane with heavy load on low- 
ered boom. This trestle is 2 
ft. high to base of rail heights 
to 30 ft. have been built, the 
stiffpiles requiring no bracing. 

Lower Cost in Place. The dif 

ference first cost between tem- 
porary and permanent, fireproof 
construction is greatly reduced by 
theeconomyof 3-large-pile bents. 

The true measure of pile economy is not cost per pile or 
foot of pile, but cost per unit of load capacity, A 
24-in. octagonal concrete pile theoretically has 2.8 
times the load capacity of an 11 -in. (av. diam.) pile. 
The capacity ratio in service may be even greater. 

The following costs reported by a mid -western railroad 
during 1934 are significant. 

Average manufacturing cost per foot of 24-in. octagon 
pile was $1.28 per lin. ft. (from $1.04 for 25 ft. to $1.59 
for 60-ft. piles). A 35-ft. pile averaged $1,185 for manu- 
facture; $0.65 for driving; $0.20 for handling and trans- 

porting; $2,035 total cost in place per foot of pile. 

To match this cost on a capacity basis at 2.8 ratio, an 
11 -in. pile would have to be obtained at a cost of only 
73 cents in place. 

Or, compare on these fair assumptions: An 11 -in. 
(35-ft.) pile at $0.50 purchasing price costs $0.95 per ft. 
in place or $33.25. At 25 tons capacity, cost per ton is 
$1.33. The capacity of a 24-in. pile would be 2.8 times 
the smaller, or 70 tons, and the cost per ton (2.035 
times 35 divided by 70) would be $1.02 — only 77 per 
cent as much as the small pile. 

Beginning New 101-Span Trestle. Left: A carload of piles 

delivered at the site. Right: Digging holes to receive the piles, 
using guide frame to insure exact driving. 

Drives as Quickly as Smaller Pile. No leads are used in driv- 
ing 24-in. concrete piles. A standard hammer of large size is used. 
Template several feet above ground holds pile vertical. 


s*i** lNG 


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S 111 D ent and P*-* 

W« P»» ^ " construct 
. of three fare r ^ ngs to = 

**» "I Vst Toe reasons . 

„ w e and cost- percent- 

*»**■• L ven b.«*«'" ^ 

piles are dr than a 

„<rer Vines. et to drw 

Each ur 6 e P* ^^ 

-*' P ts ft. tostead of * ft£ oy pl us. 
, . Spans are 18 ce nt as . 

- T ^atedlV *«*£££ toe £ 
^ and ° Pde "'tepractrcaWonf ^ e . ^ 




Stringers Are Not Disturbed! As many as 3 to 9 piles, depending 
on operating schedule, may be set in place at once and driven in a 
nearly continuous operation. 



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Cutting Off is Easy. In 12 to 20 

minutes concrete is cut away, rein- 
forcement burned through, and 
head snapped off with eccentric 
cable hitch as shown. 

Perfect Condition of these 

heads after driving shows that 
concrete piles can "take it." 
Ordinary timber cushion block 
was used. 

Perfect Splice can easily be 
made for driven piles which 
need to be lengthened. Metal 
forms such as these were used 
to make the neat splice, seen in 
nearest pile, in front-cover view. 

pica I cap reinforcement in place, 
ready for concrete. 

No Work Train needed with this 
cap concreting outfr Switched in 
and out by the pile driver crane. 
Mixing water for three caps carried 
in addition to aggregates and cemc 

For Increased Load Capac- 
ity, where required, piles may 
be surrounded at the ground 
with a concrete collar, increas- 
ing the bearing area and longi- 
tudinal stiffness of the bent. 


5° n cret er . ., 

r/, ey ro * J ^ si^? re "icreao rese rv e «? da ^c e 

7 i 

moving Old Deck. Light crane clearing 
for two nt w deck panels. Ties need not be 
removed unlew thry arc to be k newcd. 

A Day's Work ended here. Four to six panels can ordinarily be 
placed in 8 hours with no delay to operating traffic. 

Bring On Your Southbound 

Limited! Crane clearing after 
blocking up track on new slab. 

Beginning a long life and an 
economical one. 


Now for the Bal- 
last — after which 
you can practically 
forget the large-pile 
concrete trestle. 



Behind these fast-action scenes are the following interesting cost figures from 
final accounting records of a leading railroad: 

Complete cost finished trestle, $49.52 per lin. ft. 
Manufacturing cost of 24-in. piles, $1,207 per lin. ft. 
Manufacturing cost of deck slabs, $16.31 per foot of bridge. 

The figures cover a 3-pile trestle of fourteen 18-ft. panels; 13 ft. clearance; 
E-70 loading. 

A reliable comparison of total annual costs for various types of 

construction is afforded by applying the well-known formula, Annual Cost 

= C r +7T1 — nrfi — - + M+F+E+ T*. Substitution of typical fair values shows 

a cost for concrete ballasted deck of $2.84 per foot of bridge per year. Less 
permanent types of construction cost 25% to 35% more per year than the 
3-pile concrete type, according to economic analysis. 

Railway engineers and executives are invited to check these results in detail. 
The complete figures are given in Concrete Information RB 2- A i( The Large 
Pile Trestle — Economics," sent on request. 


*C. first cost; Fraction, sinking fund; 
M, maintenance; F, fire insurance; E, 
appearance value (taken as zero) ; T, 
appraised continuity-of- service value* 

ft. MO * E te «esties 

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besm^fate roa^actu ^tamcon^ r- 

; n one tefti yar d. * , stna u uv \ rrete \s ottei 

^S& :<r £^* ed con 

ca " factory c0 ^ ca tions. , - 1S locate' 

a^ sa ulprt to specif 31 he yard « 

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Typical Forms for octagonal piles. 

a " SS2 ctory <*tjg£ „ located 

11 sa ^!prt to speofica^ j, jM« » «anes. 

^ 0t :^ d C "^P ^ n «ded- 

io «stfin» 

Proper Curing of piles and slabs is the final step in developing 
high strength concrete. 

Large Concrete Piles (Concrete Information 

RB 1). A technical discussion which includes design 
sheet, cost data and specifications for constructing, 
handling and driving large premolded concrete piles. 

The Large Pile Concrete Trestle — Economics 

(Concrete Information RB 2 -A). Advantages, cost 
data and analysis of total annual costs. 

The Large Pile Concrete Trestle — Design (Con- 
crete Information RB 2-B). Standard slab and pile 
designs, with discussion of unit stresses, impact and 
other questions. 

The Large Pile Concrete Trestle — Manufacture 

and Erection (Concrete Information RB 2-C). 
Layout and operation of efficient casting yard; 
equipment and methods for driving piles, concreting 
caps and setting slabs. 

Analysis off Rigid Frame Concrete Bridges (3rd 

edition). Simple, short-cut methods of designing this 

beautiful, economical type of structure, 40 pages, 
including numerous design charts. 

Concrete Bridge Details. Discussion of abut- 
ments, bridge seats, joints and other details in light 
of conditions observed in nation-wide survey. 
48 pages. 

Vibration— A Better Method off Placing Con- 
crete. Methods, equipment and results of vibratory 
placement. 36 pages. 

Design and Control of Concrete Mixtures. 

Technical discussion of all phases cf quality con- 
crete making. 72 pages. 

The Portland Cement Association is a national 
organization to improve and extend the uses of con- 
crete. Its facilities are at your service. Any of these 
publications will be sent free on request, without 
obligation. Information sheets and booklets are also 
available on other subjects involving the use 
of concrete. 

RY-16— 5M— £-35